Adhesion Behavior of Microorganisms Isolated from Soil on Hydroxyapatite and Other Materials.

The adhesion behavior of microorganisms on different materials was examined to obtain basic knowledge for designing support materials for microorganisms. The microorganisms were isolated from soil, and their adhesion behavior on hydroxyapatite (HA), carbon-coated HA (Carbon), poly (vinyl chloride) (PVC), and polyurethane (PU) pellets was investigated. The total metabolic activity on and adherence of microorganisms to the tested materials were in the following order: HA > Carbon > PVC > PU.

Diversity of multinucleated giant cells by microstructures of hydroxyapatite and plasma components in extraskeletal implantation model.

Unlabelled: Foreign body giant cells (FBGCs) and osteoclasts are multinucleated giant cells (MNGCs), both of which are formed by the fusion of macrophage-derived mononuclear cells. Osteoclasts are distinct from FBGCs due to their bone resorption ability; however, not only morphological, but also functional similarities may exist between these cells. The characterization and diversity of FBGCs that appear in an in vivo foreign body reaction currently remain incomplete.

Effect of silicate incorporation on in vivo responses of α-tricalcium phosphate ceramics.

In addition to calcium phosphate-based ceramics, glass-based materials have been utilized as bone substitutes, and silicate in these materials has been suggested to contribute to their ability to stimulate bone repair. In this study, a silicate-containing α-tricalcium phosphate (α-TCP) ceramic was prepared using a wet chemical process. Porous granules composed of silicate-containing α-TCP, for which the starting composition had a molar ratio of 0.

Spherical porous hydroxyapatite granules containing composites of magnetic and hydroxyapatite nanoparticles for the hyperthermia treatment of bone tumor.

Spherical porous granules of hydroxyapatite (HA) containing magnetic nanoparticles would be suitable for the hyperthermia treatment of bone tumor, because porous HA granules act as a scaffold for bone regeneration, and magnetic nanoparticles generate sufficient heat to kill tumor cells under an alternating magnetic field. Although magnetic nanoparticles are promising heat generators, their small size makes them difficult to support in porous HA ceramics. We prepared micrometer-sized composites of magnetic and HA nanoparticles, and then supported them in porous HA granules composed of rod-like particles.

Adhesion behaviors of Escherichia coli on hydroxyapatite.

Optimum design of support materials for microorganisms is required for the construction of bioreactors. However, the effects of support materials on microorganisms are still unclear. In this study, we investigated the adhesion behavior of Escherichia coli (E.

Importance of nucleation in transformation of octacalcium phosphate to hydroxyapatite.

Octacalcium phosphate (OCP) is regarded as an in vivo precursor of hydroxyapatite (HA). It is important to understand the mechanism of transformation of OCP to HA in order to reveal the mechanism of mineralization and help in the development of artificial bone-repairing materials. Herein, we have examined the behavior of OCP in a simulated body fluid (SBF) and pure water.

Promotion of normal healing of bone defects under estrogen deficiency by implantation of beta-tricalcium phosphate composed of rod-shaped particles.

We compared the healing of bone defects in ovariectomized rats implanted with beta-tricalcium phosphate (b-TCP)composed of rod-shaped particles, which were prepared using the applied hydrothermal method (HTCP), and that of bone defects implanted with conventional b-TCP composed of globular-shaped particles (CTCP), which were prepared by normal sintering. Eight week-old female Wistar rats were ovariectomized, and 2 weeks after the operation, 0.5- to 0.

A bone substitute with high affinity for vitamin D-binding protein--relationship with niche of osteoclasts.

The biological activity of osteoblasts and osteoclasts is regulated not only by hormones but also by local growth factors, which are expressed in neighbouring cells or included in bone matrix. Previously, we developed hydroxyapatite (HA) composed of rod-shaped particles using applied hydrothermal methods (HHA), and it revealed mild biodegradability and potent osteoclast homing activity. Here, we compared serum proteins adsorbed to HHA with those adsorbed to conventional HA composed of globular-shaped particles (CHA).

Behavior of osteoblast-like cells on calcium-deficient hydroxyapatite ceramics composed of particles with different shapes and sizes.

In designing the biomaterials, it is important to control their surface morphologies, because they affect the interactions between the materials and cells. We previously reported that porous calcium-deficient hydroxyapatite (HA) ceramics composed of rod-like particles had advantages over sintered porous HA ceramics; however, the effects of the surface morphology of calcium-deficient HA ceramics on cell behavior have remained unclear. Using a hydrothermal process, we successfully prepared porous calcium-deficient HA ceramics with different surface morphologies, composed of plate-like particles of 200-300, 500-800 nm, or 2-3 μm in width and rod-like particles of 1 or 3-5 μm in width, respectively.

Preparation and evaluation of spherical Ca-deficient hydroxyapatite granules with controlled surface microstructure as drug carriers.

Spherical Ca-deficient hydroxyapatite (HA) granules are expected to be useful drug carriers in bony sites because of their bone regeneration and adsorption ability. In order to control drug loading and release ability of the granules, a controlled surface microstructure was constructed. Spherical Ca-deficient granules composed of micron-sized rod-shaped particles were prepared by hydrothermal treatment of α-tricalcium phosphate (α-TCP) granules, and then, submicron HA particles were precipitated on the obtained granules by immersion in a supersaturated calcium phosphate (CP) solution.

Stimulation of Osteogenesis in Bone Defects Implanted with Biodegradable Hydroxyapatite Composed of Rod-Shaped Particles under Mechanical Unloading.

The aim of this study was to evaluate the influence of mechanical unloading on the repair of bone defects with implantation of biodegradable bone substitutes. Spherical granules of biodegradable hydroxyapatite composed of rod-shaped particles (RHA) or beta-tricalcium phosphate composed of rod-shaped particles (RTCP) were implanted into a bone defect created in the distal end of the right femur of 8-week-old Wistar rats. Two, 6, 10, and 22 weeks after implantation, part of the sciatic nerve in the thigh was resected and exposed to mechanical unloading for 2 weeks.

Synthesis of nanosized porous hydroxyapatite granules in hydrogel by electrophoresis.

Nanosized porous hydroxyapatite (HA) granules are expected to be useful as DNA and drug carriers for cells. We attempted to synthesize nanosized HA granules in an agarose gel by electrophoresis of calcium and phosphate ions. Wells were prepared on an agarose gel, and a CaCl(2) solution was placed in the wells on the positive side and a Na(2)HPO(4) solution was placed in the wells on the negative side.

Lateral bone augmentation with newly developed β-tricalcium phosphate block: an experimental study in the rabbit mandible.

Objective: To evaluate the biological effects of newly developed β-tricalcium phosphate (β-TCP) to improve lateral bone augmentation.

Material And Methods: Test samples (rod-shaped [RS]-blocks) were prepared through hydrothermal processing α-TCPs. As controls, commercially available β-TCPs (C-blocks; Osferion) were used.

Preparation and biological evaluation of a fibroblast growth factor-2-apatite composite layer on polymeric material.

A polymeric percutaneous device with good biocompatibility and resistance to bacterial infection is required clinically. In this study, a fibroblast growth factor-2 (FGF-2)-hydroxyapatite (HAp) composite layer (FHAp layer) was formed on the surfaces of ethylene-vinyl alcohol copolymer (EVOH) specimens using a coating process in a supersaturated calcium phosphate solution supplemented with FGF-2. FGF-2 in the FHAp layer retained its biological activity to promote proliferation of fibroblasts.

Stimulatory effect of hydrothermally synthesized biodegradable hydroxyapatite granules on osteogenesis and direct association with osteoclasts.

Calcium-deficient hydroxyapatite (HA) granules with a unique spherical shape were prepared using an applied hydrothermal method. Spherical stoichiometric HA granules were also prepared by normal sintering and both granules were used for implantation into rat tibiae to compare the biological responses to each implant. Twelve and 24 weeks after implantation, the volume of calcium-deficient HA granules was significantly less than that of stoichiometric HA granules, and the biodegradability of calcium-deficient HA granules was confirmed.

The slow resorption with replacement by bone of a hydrothermally synthesized pure calcium-deficient hydroxyapatite.

A newly developed calcium-deficient hydroxyapatite composed of rod-shaped particles synthesized by the hydrothermal method (HHA) and stoichiometric hydroxyapatite (SHA) synthesized by the sintering method was used for in vivo implantation and in vitro culture systems to compare these biological responses. In the rabbit femur, implanted HHA was slowly resorbed and about 80% of the implant remained 24 weeks after implantation; however, up to 72 weeks after implantation, most of the implanted HHA was resorbed. The implanted SHA was unresorbed throughout the experimental period, but degradation by the invasion of newly formed bone was seen at 72 weeks after implantation.

The effect of the microstructure of beta-tricalcium phosphate on the metabolism of subsequently formed bone tissue.

The response of bone cells to a newly developed porous beta-tricalcium phosphate composed of rod-shaped particles (RSbeta-TCP), beta-TCP composed of conventional non-rod-shaped particles (Cbeta-TCP), and hydroxyapatite (HA) was analyzed using in vivo implantation and in vitro osteoclastogenesis systems. Implantation of the materials into the rabbit femur showed that RSbeta-TCP and Cbeta-TCP were bioresorbable, but HA was not. Up to 12 weeks after the implantation, bioresorption of RSbeta-TCP and Cbeta-TCP accompanied by the formation of new bone occurred satisfactorily.

Observation and quantitative analysis of rat bone marrow stromal cells cultured in vitro on newly formed transparent beta-tricalcium phosphate.

To observe living cell morphology on ceramics by light microscopy, we fabricated a new material-transparent beta - tricalcium phosphate (t-beta TCP) ceramic-for the purpose of serving as a tissue culture substrate. Bone marrow stromal cells (BMSCs) were obtained from rat femora and cultured on both t-beta TCP ceramic disks and culture grade polystyrene (PS) dishes in an osteogenic medium. After 1 day of culture, cell attachment and spreading on both the t-beta TCP and PS substrata were equally and clearly detected by ordinary light microscopy.

Observation of osteogenic differentiation cascade of living mesenchymal stem cells on transparent hydroxyapatite ceramics.

The use of bioceramics and cultured cells for tissue engineering is a novel approach, which is available in a wide variety of clinical situations. The approach requires apparent verification of the cellular functions occurring on the ceramic surface, and these functions could be monitored by microscopic observation of the cultured living cells on the ceramic material. However, such observation is difficult due to the opaque nature of ordinary ceramics.